Yamaha YBR125ED 2005 Service Manual page 61

ADJUSTING THE VALVE CLEARANCE
M MMM M MMM M M MMM
a. Turn the crankshaft counterclockwise.
b. When the piston is at TDC on the compres-
sion stroke, align the "I" mark a on the A.C.
magneto rotor with the stationary b on the
A.C. magneto rotor cover.
c. Align the "I" mark c on the camshaft
sprocket with the stationary pointer d on
the cylinder head.
d. Measure the valve clearance with a thick-
ness gauge 1.
Thickness gauge
90890-03079, YM-34483
Out of specification → Adjust.
L LLL L LLL L L LLL
6. Adjust:
• valve clearance
M MMM M MMM M M MMM
a. Loosen the locknut 1.
b. Insert a thickness gauge 2 between the
end of the adjusting screw and the valve tip.
c. Turn the adjusting screw 3 in direction a
or b until the specified valve clearance is
obtained.
Direction a
Direction b
Tappet adjusting tool
90890-01311, YM-08035-A
3 - 8
CHK
ADJ
M M MMM M M MMM M
L L LLL L L LLL L
M M MMM M M MMM M
Valve clearance is
increased.
Valve clearance is
decreased.
M MMM M MMM
L LLL L LLL
M MMM M MMM